The Congressional Research Service (CRS) was established within the Library of Congress to provide members, committees, and congressional staff with nonpartisan and objective research and analysis on all public policy issues. Originally established in 1914 as the Legislative Reference Division, CRS was originally organized as a typical library reference service. Under the Legislative Reorganization Act of 1946, it was officially named the Legislative Reference Service, given permanent status as a separate department within the Library, and directed to employ senior specialists in various program areas. The Legislative Reference Service was renamed Congressional Research Service under the Legislative Reference Act of 1970.

Currently, the CRS research divisions are: American Law; Domestic Social Policy; Foreign Affairs, Defense and Trade; Government and Finance; Knowledge Services; and Resources, Science and Industry. Many CRS reports are updated at varying intervals, so it is always important to note the exact date of issuance rather than just the title and the year of publication.